High-Coercivity in $\alpha\hbox{-}{\rm Fe}_{2}{\rm O}_{3}$ Formed After Annealing From ${\rm Fe}_{3}{\rm O}_{4}$ Nanoparticles

Hematite particles (α-Fe
₂
O
₃
) were synthesized by oxidation of Fe
₃
O
₄
nanoparticles through heat treatment in the atmosphere of 95% N
₂
plus 5% O
₂
. This method can result in an effective fabrication of high-coercivity α-Fe
₂
O
₃
particles. The Morin transition of the as-prepared α-Fe
₂
O
₃
particles was detected to be 265 K, and a coercivity of 6.2 kOe could be observed at room temperature. The magnetic properties at different temperatures of the as-produced α-Fe
₂
O
₃
particles were studied.